Thiosemicarbazone fungicides

ABSTRACT

AND THE R&#39;&#39;S ARE INDEPENDENTLY HYDROGEN OR LOWER ALKYL OF C1-C4. IT FURTHER RELATES TO CONTROLLING FUNGI AND PROTECTING CORPS FROM ATTACK BY FUNGUS ORGAANISMS WITH THE ABOVE COMPOUND.   -C(-R&#39;&#39;)2-C(-)(-R&#39;&#39;)2-C(-R&#39;&#39;)2-   -C(-R&#39;&#39;)=C(-R&#39;&#39;)-, -C(-R&#39;&#39;)2-C(-R&#39;&#39;)2-, AND   WHEREIN R IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF   R2&#39;&#39;-C(=S)-NH-N=C&lt;(-S-R-S-)   THE PRESENT INVENTION RELATES TO COMPOUNDS OF THE FORMULA:

United States Patent US. Cl. 424-277 7 Claims ABSTRACT on THE DISCLOSURE The present invention relates to compounds of the formula:

wherein R is a member selected from the group consisting of (kR'= R, R'zbR'g and lR'gR'fl R'g, and the Rs are independently hydrogen or lower alkyl of C C It further relates to controlling fungi and protecting crops from attack by fungus organisms with the above compound.

This is a divisional of application, Ser. No. 227,287, filed on Feb. 17, 1972, now Pat. No. 3,761,492, issued on Sept. 25, 1973.

This invention relates to novel compounds having the formula:

wherein R is a member selected from the group consisting of and the Rs are independently hydrogen or lower alkyl of C -C It further relates to a method for controlling fungi with the above-identified compounds and to the use of such compounds for protecting agronomic crops, both growing and harvested, from attack by pathogenic fungus organisms.

The above compounds can be synthesized by reacting the acid salt of the appropriate 2-imino derivative of 1,3- dithiole, 1,3-dithiolane or 1,3-dithiane and thiosemicarbazide or the appropriate derivative thereof.

Reaction is conveniently induced by admixing the iminodithiole, dithiolane or dithiane with the selected thiosemicarbazide in suiiicent amount to provide a mole ratio of the heterosulfur compound to the thiosemicarbazide of from 1: 1.5 to 1.5 to 1. The temperature of the mixture is maintained between about 50 C. and 125 C. The pH of the reaction mixture is maintained below 7.0. The reaction is conducted in the presence of a solvent selected from the group consisting of water, lower alkyl alcohols and mixtures thereof. Suitable loweralkyl alcohols include methanol, ethanol, isopropanol, n-propanol, n-butanol and 2-butanol.

In a preferred embodiment of the above process approximately equimolar amounts of the hetero sulfur compound and the thiosemicarbazide are utilized. Also, the temperature of the reaction mixture is preferably maintained between about 75 C. and 70 C., the pH is maintained between 1.0 and 6.0 and the preferred solvent is water.

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Moreover, it has been found that the bisulfate, hydrochloride and hydrobromide salts of the Z-imino-dithioles, dithiolanes or dithianes may be used in the instant process, however, the bisulfate salts appear to be the preferred species.

These reactions may be graphically written as follows:

S S S S R NHHX were. A

wherein R and R are as defined above and X is S05, Br or Cl Illustrative compounds of Formula I include, for example,

4-methyl-1,3-dithiolan-2-one thiosemicarbazone, 4,5-dimethyl-1,3-dithiolan-2-one thiosemicarbazone, 4-n-butyl-1,3-dithiolan-2-one thiosemicarbazone, 1,3-dithian-2-one thiosemicarbazone, 4,4-dimethyl-1,3-dithiolan-2-one thiosemicarbazone, 1,3-dithiolan-2-one thiosemicarbazone, 4-methyl-1, 3-dithiol-2-one thiosernicarbazone, 1,3-dithiolan-2-one 4-methylthiosemicarbazone, 4-ethyl-1,3-dithiolan-2-one thiosemicarbazone, 1,3-dithiolan-2-one 4,4-dibutyl thiosemicarbazone, 4,4,5,5tetramethyl-l,3-dithiolan-2-one thiosemicarbazone, 4,5-dimethyl-1,3-dithiol-2-one thiosemicarbazone, 4-methyl-1,3-dilhian-2-one thiosemicarbazone, 4,5,6-trimethyl-1,3-dithian-2-one thiosemicarbazone,

and the like.

Methods for the preparation of the 2-imino-1,3-dithioles, 2-imino-1,3-dithiolanes and 2-imino-1,3-dithianes (i.e., the starting materials for the compounds of the pres ent invention) are described in the Addor U.S. Pats. 3,197,481, 3,364,230, 3,389,147, 3,193,561, and the Lies U.S. Pats. 3,342,835 and 3,449,366.

For use in controlling fungi, the above compounds are brought into contact with the fungi to be controlled. For ease in application, one or more of the active ingredients is preferably formulated in effective or .fungitoxic amount with a conventional agricultural adjuvant, such as a solid or liquid inert carrier, diluent or other formulation aid.

For use in the treatment or protection of growing plants or agronomic crops from pathogenic fungi, the compounds are applied to the crops to be protected. The compounds are preferably formulated as dusts, dust concentrates, wettable powders or the like, and applied by conventional equipment, as by spraying or dusting the foliage of said plants or harvested crops.

Dusts are usually prepared by grinding together from about 1% to 15% by weight of the active ingredient and from about 99 to by weight of a finely divided inert diluent or carrier. Kaolin, attapulgite, diatomaceous earth, talc and fullers earth are typical carriers useful in the preparation of such dust formulations. If desired, it has also been found that sticking agents may be incorporated in these formulations but are not essential.

Dust concentrates are prepared in the same manner as the more dilute dusts but generally contain from about 25% to by weight of the toxicant. In addition to the grinding method referred to above, it is noted that these formulations may also be prepared by dissolving the toxicant in hot acetone or methylene chloride and spraying the toxicant solution on a tumbling bed of a finely divided solid inert carrier. Any of the solid carriers described above may be employed in these formulations.

Wettable powders are usually prepared in the same manner as the dust formations excepting that in addition to the toxicant and carrier there is also generally added from about 1% to by weight of a dispersing agent such as an alkali metal lignosulfonate and from about 1% to 5% by weight of a wetting agent. Wetting agents such as sodium N-methyl-N-oleoylturate and sodium alkylnaphthalene sulfonate are suitable for this purpose.

In practice, the wettable powders are generally dispersed in water or other relatively inexpensive liquid such as deodorlzed kerosene and applied to the crops sought to be protected, as liquid sprays. From about to 400 gallons of liquid, containing from about A to 8 lbs. of active ingredient is generally used per acre of crops being treated.

Typical wettable powder formulations are set forth Attaclay by the Attapulgus Clay Company.

The invention and preparation of the active ingredients are further illustrated by the examples set forth below, which are not to be taken as being limitative thereof. Unless otherwise specified, all parts and percentages are by weight.

EXAMPLE 1 Preparation of 4-methyl-1,3-dithiolan-2-one thiosemicarbazone ore-r 4-Methyl-2-imino-1,3-dithiolane hydrochloride (12.0 g., 0.0707 mole) was dissolved in 100 ml. of water and filtered into a 500 ml. round-bottomed flask equipped with a mechanical stirrer, reflux condenser, and thermometer. Thiosemicarbazide (6.45 g., 0.0707 mole) was added with stirring and the reaction mixture was heated on a steam bath to C. and held there for about 5 minutes. During the heating, complete solution was observed before the product precipitated. After slow cooling and standing for 2 hours, the white solid was collected on a Buchner funnel, washed with water, and dried in vacuum desiccator over KOH to give 7.3 g., m.p. 163164 C.

A second crop, which crystallized in the mother liquor, was filtered, washed, and dried: wt., 1.2 g., m.p. 162- l63C. The combined crops (8.5 g., 58% yield) were recrystallized from 250 ml. of absolute ethanol to give 7.2 g., m.p. 163-164 C. (with bubbling).

Analysis.-Calcd. for C H N S C, 28.96; H, 4.38; N, 20.27; S, 46.40. Found: C, 28.75; H, 4.40; N, 20.09; S, 46.37.

After standing for a week, the reaction mother liquor yielded an additional 4.6 g. of long needles, mp. 163 164 C. (with bubbling), to bring the total yield to For most of the compounds, the reaction mixture was allowed to stand overnight before filtration of crude product, and no attempt was made to recover further crops.

EXAMPLE 2 Preparation of 4-methyl-1,3-dithiol-2-onethiosemicarbazone To the imino compound hydrochloride (0.15 mole, 30.8 g.) in 200 ml. of water was added thiosemicarbazide (0.15 mole, 13.7 g.). The reaction mixture was heated to 85 C. when solid began to precipitate. The mixture was cooled and allowed to stand. Several solid crops formed. The best appeared to be third: wt., 3.7 g.; m.p. 119.5-124 C.

Recrystallization from methanol gave 2.7 g. of yellow solid, mp. 145.5-146 C. Recrystallization from isopropanol gave 1.3 g. of off-white solid, mp. 149151 C.

Analysis.-Calcd. for C H N S C, 29.26; H, 3.44; N, 20.46; S, 46.85. Found: C, 29.40; H, 3.28; N, 20.54; S, 46.96.

EXAMPLES 3-8 By utilizing the procedure of Example 1 above and substituting the hydrochloride salt of the appropriate hetero sulfur compound and selected thiosemicarbazide for their appropriate counterparts, the compounds set forth in Table 11 below were prepared.

TABLE II Analysis Reaction Calcd. Found Example Time, Temp, number Compound minutes C. M.P.. C. C H N S C H N S 3 CH3 S 10 65 5 -183 32. 55 5. 01 18. 98 43. 46 32. 35 5. 53 19. 10 43. 25

i =N-NH-C S NH2 CH; S

4 fl-C4Hn -S 10 74 137 139 38. 52 6.06 16. 85 38.57 38. 80 6.06 16. 86 38. 69

=NNHO S NH2 S TABLE IL-Co-ntinued Analysis Reaction Calcd. Found Example Time, Temp., M.P. number Compound minutes 0. C. G H N S O H N S S C I =NNH-CSNH1 =N-NH-C S -NHCH:

I =NNHC S -N H:

- Melts with decomposition.

EXAMPLES 9-13 Following the procedure of Examples 1 or 2 above, the following reactions are effected."The compounds produced thereby are set forth in Table III below.

TABLE III EXAMPLE 22 The foliage of Bonnie Best Tomato plants with 4 true leaves, and Early Marketeer cucumber plants with 2 true leaves were sprayed with 50/50 acetone/water solutions -1 Solvent t 1 EXAMPLES 14-21 Following the procedure of Example 1 above the following reactions are effected-The compounds produced thereby are set forth in Table IV below.

containing ppm. or 500 p.p.m. of test compound. All plants were sprayed to run-ofit. The plants were allowed to dry and were then sprayed with a mixed inoculum of Phytophthom infestans (late blight) and Col- TABLE IV R4 S R 4 a a R5 R0 R5 R0 Substitutents Mole Iemp., ratio, Example number R1 R1 R2 R4 Ra Re R1 Rs 12 C. Solvent 0:

letotrichum lagenarium (anthracnose). Immediately thereafter the inoculated plants were placed in a constant temperature cabinet at 62 F. and a saturated atmosphere. After 24 hours the temperature Was advanced to 70 F. and held there for 72 hours at which time the plants were removed to the greenhouse. Readings on discase control were made 7 days after inoculation, using the following ratings of disease observed: =no disease; TABLE VI 4=trace; 3=slight; 2=moderate; 1=severe disease. The Rate Percent results are set forth in Table V below. 10 Compound p p,m, control TABLE V.RESULTS OF FOLIAR SPRAY PROTECTIVE s 50 300 TESTS 5 200 9613 l =N-NHGNH Disease rating s Cue. anthrac. Tom. late blight Zineb 50 31.3 500 100 500 100 200 78. 8 Compound p.p.m. p.p.m. p.p.m. p.p.m. Inoculated check 0. 0

s 5 5 5 5 NNHCSNH2 We clall'IlZ I F 1. A method for controlling fungi or protecting a growing plant from attack by pathogenic fungi which comprises: applying to said plant or fungi a fungitoxic amount s 4 a 5 4 CH3 NNHC SNH2 of a compound having the formula: Li r T S 4 3 5 5 R :NNH JNR;

L n-Bu- NNH-CS-NH2 s where R is a member selected from the group consisting S 4 a 5 5 CH; -N-NHCSNH: oaeca haven. and onz'om'om',

said Rs each being hydrogen or lower alkyl of from 1 CH3 5 to 4 carbon atoms.

3 1 5 4 2. The process according to Claim 1 wherein the com- 30 pound is 4-methyl-l,3-dithiolan-2-one-thiosemicarbazone.

UNITED STATES PATENTS 7/1965 Addor 260327 9/1969 Addor 260327 ALBERT T. MEYERS, Primary Examiner A. JAY ROBINSON, Assistant Examiner 

